| Influence of H+ and calcium ions on surface functional groups of Synechococcus PCC 7942 cells. | |
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MedLine Citation:
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PMID: 16732674 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The chemistry of the surface functional groups of picocyanobacteria Synechococcus PCC 7942 cells was examined as a function of H+ and calcium concentrations. Titration experiments, infrared spectroscopy, biosorption experiments, and chemical modeling were used to gain insight into the mechanisms of biosorption. The pKa and concentration of active sites on the cell wall were clarified with the aid of potentiometric titration. Modeling calculations and infrared spectra are consistent with pKa's values of 4.3, 5.2, 6.9, 9.1, and 10.0 and a total concentration of 7.8 x 10(-4) mol g(-1). Spectral analysis of an aqueous cellular suspension revealed a presence of carboxyl, amide, phosphate, hydroxyl, and carbohydrate moieties. Correspondence between spectral data and potentiometric titration curves supported the hypothesis that carboxylate groups and phosphodiester groups mediate calcium adsorption to bacterial cells. This process is strongly pH dependent. In the second part of the experimental work, Synechococcus cells were suspended in the presence of different calcium concentrations. Mechanistic modeling demonstrated that the calcium adsorption phenomenon can be described taking into account only two mechanisms: ion exchange and complexation. |
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Authors:
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Maria Dittrich; Sabine Sibler |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Langmuir : the ACS journal of surfaces and colloids Volume: 22 ISSN: 0743-7463 ISO Abbreviation: Langmuir Publication Date: 2006 Jun |
Date Detail:
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Created Date: 2006-05-30 Completed Date: 2007-07-24 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9882736 Medline TA: Langmuir Country: United States |
Other Details:
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Languages: eng Pagination: 5435-42 Citation Subset: IM |
Affiliation:
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Swiss Federal Institute of Aquatic Science and Technology, Eawag, Switzerland. dittrich@eawag.ch |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Absorption Calcium / metabolism*, pharmacology Hydrogen-Ion Concentration Models, Biological* Spectrophotometry, Infrared Synechococcus / chemistry, metabolism* Titrimetry |
| Chemical | |
Reg. No./Substance:
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7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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